main(n,k,i)
{
	long r;
	for(gets(&n);~scanf("%d%d",&n,&k);printf("%ld\n",r))
	{
		k=k>n-k?k:n-k;
		for(r=1,i=k+1;i<=n;i++)
			r=r*i/(i-k);
	}
}
